A strain pattern often presents with significant ST-elevation in the right precordial leads (V1 – V3) which is the main reason that it can mimic acute anterior STEMI. Often the ST-elevation can be quite dramatic.

Here the ST-elevation in the right precordial leads (V1-V3) is impressive. However, the S-waves are very deep! This is the big tip-off that we're dealing with a STEMI mimic.

In this case the patient was cathed because he experienced a VF arrest while on the treadmill at cardiac rehab. You can't blame anyone for sending a patient like that to the cardiac cath lab!

What they found was extensive coronary artery disease and chronically occluded vein grafts but no acute thrombosis in the LAD.

Interestingly, Stephen Smith, M.D. from Dr. Smith's ECG Blog has stated that he has only seen one or two LAD occlusions in his entire career that met the conventional LVH criteria in the right precordial leads! Why should this be?

He theorizes that perhaps acute STEMI attenuates the S-wave voltage in the right precordial leads in the setting of pre-existing LVH.

We were unable to obtain an "old" ECG for comparison, but based on the appearance of lead V1 it certainly looks as if this ECG met the LVH criteria in the precordial leads prior to the development of pathological Q-waves in leads V2 and V3.

A "strain pattern" (evidenced by ST-depression and T-wave inversion) is still present in the high lateral leads (I and aVL).

The S-wave depth measures 23 mm in lead V1 and 29 mm in lead V2! The R-wave amplitude measures 12 mm in lead V5 and 13 mm in lead V6. So, if we add the S-wave depth in lead V2 and the R-wave height in lead V6 we get 44 mm (cut-off is 35 mm) so this meets the most commonly used voltage criteria for LVH.

Here's how I'm measuring the S-waves (see comments).

Here's a close-up of the right precordials from another ECG that was submitted with the case study that I didn't publish earlier due to poor data quality in the limb leads. Here you can see the separation a little bit better.

Based on this I would expect a significant ST/T wave abnormality in the opposite direction! To me the most striking thing about this case is the absence of significant ST-elevation in leads V1 and V2.

Having said that, the ST-depression and T-wave inversion in leads with an upright QRS complex are almost certainly due to left ventricular hypertrophy.

Brandon, I calculate out the same as you. Using ESTES LVH criteria I get 6 points (>=5 diagnostic) due to >30mm S in V1 or V2 (+3) and secondary ST-T abnormalities with widened QRS/T angle (+3).
Beyond that, the way the ST-T goes opposite the QRS and flips with the R-wave progression sort of sold me on "secondary ST-T abnormality" rather than "primary". Especially with the global nature.

Brandon – This is why (one presumes) the ZOLL machine "crops" the QRS complexes so that they don't run into one another. I prefer it when the machine does not crop the QRS complexes, but the measurements can become difficult. This problem could be solved by creating a user interface that allows the paramedic to easily print out individual leads in diagnostic quality. At any rate, I did not measure the QRS complexes the way that you did. I created an image that shows where I think the QRS complexes begin and end. Thanks, Tom

Tom, perhaps Zoll could improve the cropping situation by placing a crop marker of some kind when it does that. They could then include in the interpretive statements: V1 S-WAVE CROPPED, TOTAL AMPLITUDE -4.4 mV

Brandon – I just added another image showing V1-V3 in higher resolution. I’m not smart enough to answer your question about pathologies that could lead that that large of a voltage difference in a contiguous precordial lead, but I’m certainly not saying it’s impossible!

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Vince DiGiulio59 Year Old Female: Intermittent Head Pain (Conclusion)Thanks! There's a couple of reasons why V7-9 might have been negative here: 1) Not all "inferoposterior" STEMI's show ST-elevation in V7-V9. Sometimes the ST-depression we see in V2 and V3 is reciprocal to the inferior STEMI and not really caused by posterior injury. 2) You'll notice that there is only subtle ST-depression in V3…
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